Area Forecast Discussion
Issued by NWS Jackson, KY

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928
FXUS63 KJKL 200550 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1250 AM EST Mon Nov 20 2017

.UPDATE...
Issued at 1230 AM EST MON NOV 20 2017

Did a quick update to fine tune sky cover through the rest of the
night - addressing the lingering low ones in the far east. Did
also adjust the T and Td grids to reflect the latest obs and
trends. These have been sent to the NDFD and web servers.

UPDATE Issued at 1057 PM EST SUN NOV 19 2017

Other than a few patches of low stratus near the Virginia border,
clear skies have taken hold. May see a few cirrus make it in from
the northwest later tonight, but temperatures will continue to
steadily drop into the low-mid 20s.

UPDATE Issued at 646 PM EST SUN NOV 19 2017

Low stratus slowly scouring out across eastern Kentucky. Will see
this trend continue this evening into tonight downstream of high
pressure building in from the lower to mid Mississippi Valley.
Will monitor valley temperatures through the evening as clouds
push east and winds further diminish.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 344 PM EST SUN NOV 19 2017

A shortwave moving across the Ohio Valley this morning is currently
exiting to the east this afternoon. This has impacted the CWA,
keeping moisture in the form of low clouds across the region as well
as some sprinkles (and flurries in the highest terrain) throughout
the morning and early afternoon. As this shortwave continues to
shift eastward, expect these sprinkles/flurries to taper off over
the next few hours. Latest satellite imagery shows the back edge of
the llvl clouds now over central Kentucky nudging towards our CWA.
Expect clouds to begin clearing out late this afternoon and into the
evening from west to east.

As we head into the overnight, an area of surface high pressure will
begin nosing in from the SW, and should be located across the CWA by
12Z Monday. Winds will turn more SW as the system approaches, then
remain S to SW through the day Monday and into Monday night as it
slowly shifts eastward. Made adjustments to the valley winds and
temps, lowering them based on the decoupling that is likely to take
place with high pressure overhead, especially Monday night under the
more southerly flow. Meanwhile, southerly flow will help to boost
temps on Monday afternoon back to around 50 degrees in most
locations. Latest soundings show a very dry airmass in place across
the region with the incoming high, so expect mostly clear skies
throughout the remainder of the short term forecast period after
clearing clouds this evening. While a few patches of fog can`t be
ruled out in the most sheltered valleys, the overall likelihood of
fog is fairly low based on how dry the latest soundings are,
therefore kept out of forecast.

.LONG TERM...(Tuesday through Sunday)
Issued at 344 PM EST SUN NOV 19 2017

The period will be dominated by a general longwave trough over the
eastern CONUS, and periodic impulses rotating through to affect
the trough`s amplitude and position. At the surface, these
impulses are expected to support a cold front moving through our
area Tuesday night, another cold front which dies as it approaches
the Ohio Valley Thursday night, and a strong cold front expected
to pass through our area next weekend. No significant moisture
return is forecast ahead of the fronts. In the 12Z model runs,
the GFS does generate light precip over our northeast counties on
Saturday, and its ensemble mean shows light precip over our area
on Saturday into Saturday evening. Have allowed for a slight
chance of showers over our northeast counties in those periods,
with that being the only mention of precip during the long term
period.

For temps, a couple of brief mild spells are forecast in the warm
air advection immediately ahead of the cold fronts. Otherwise,
readings are expected to be near or below normal.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1250 AM EST MON NOV 20 2017

VFR conditions will dominate through the period as just a few
patches of low stratus pushes hold on in the far east. High
pressure building in from the lower-mid Mississippi Valley will
keep any cloud cover confined to a few cirrus through Monday
afternoon as winds back southwesterly to southerly at generally 5
knots or less. Some patchy fog reported at SME this hour may
linger so have added a tempo for some MVFR BR there through 10z
when the drier air should be more firmly in place also include a
touch at LOZ for similar reasons.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...GREIF
SHORT TERM...JMW
LONG TERM...HAL
AVIATION...GREIF



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